Using perspex/plexiglass "clip frame" for cyanotype contact printing

[Ben Rush]

Hi all -
I have a quick question - I have a cyanotype workshop with younger folks coming up. With safety in mind and the side bonus of saving cash, I'm wondering I could use cheap-o plexiglass clip frames that you can pick up on amazon for contact printing. My impression is that plexiglass/acrylic/perspex artificial glass knocks out a fair amount of UV. Anyone know how much effect it will have? Does that grade of plastic knock out so much that they are best avoided?

Keep in mind I'm in Scotland, so we tend to have overcast days. If we were in Arizona, I'd not be worried!

 

[pdeeh]

I spent a rainy august bank holiday in roath park Cardiff last year making a dozen cyanotypes using clip frames with acrylic "glass" . I think they were Ikea ones.
worked fine.

 

[Ben Rush]

Thanks for replying - that's what I was hoping to hear! Do you recall what your exposure times were? With glass I typically get 7 or 8 minutes under glass on a sunny day.

 

[pdeeh]

actually there was a bit of downside come to think of it, which is that if the acrylic isn't very thick it can bow a bit and not provide good contact.
not too much of a problem if you are using plants and whatnot but could be tricky using negatives

 

[pdeeh]

Thanks for replying - that's what I was hoping to hear! Do you recall what your exposure times were? With glass I typically get 7 or 8 minutes under glass on a sunny day.

it was a horrid day, thick dense cloud when it wasn't raining. the exposure times were 30 mins or so I think.

I'd done tests the week before in proper sun and couldn't distinguish between acrylic and glass frames in any way

 

[Ben Rush]

I think we'll be ok - it's going to be cut-outs and leaves and the like.